Conventional chain conveyors, which support the products or articles to be conveyed on the pins of the chains, provide very little freedom of lateral movement of the product on the pins, due to the relatively small support or guide area of the pins and/or the product. A particular difficulty arises when transporting products such as printed circuit boards, because the boards are oftentimes warped, worn or otherwise not square. Occasionally, the board will be warped to such an extent that a corner of the board will "curl up" and not be supported at all by the conveyor, thus decreasing the effective width of the product and the resultant support surface area.
Furthermore, the width of the support area of the printed circuit boards, due to the placement of components close to the edges of the board, can be as little as approximately 0.090 inches or less. Therefore, even minor variations in the effective width of the board will affect the ability of the chain to support it. If the width between the guides changes, beyond the tolerance permitted by the support surface area of the product and/or pins, the product will not be accurately conveyed.
When conveying sturdier products that are less likely to warp or wear and which do not have support surfaces of such critical dimensions, the width of the pin alone determines the effective support surface area. In this instance, a difficulty still arises if the conveyor itself warps or wears.